The heartbeat in vertebrates originates from signals produced by the __________.
a. spinal cord
b. adrenal glands
c. medulla oblongata
d. hypothalamus
e. heart itself
Answer: e. heart itself
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Homologous recombination has been observed in
A) Archaea. B) Bacteria. C) Eukarya. D) Archaea, Bacteria, and Eukarya.
The ________ of water is caused by the unequal sharing of electrons between oxygen and hydrogen atoms.
Fill in the blank(s) with the appropriate word(s).
At chemical equilibrium
A. no reactions are occurring in either direction. B. there are no more products being formed. C. there are no more reactants for the cell to utilize. D. the amount of reactants is equal to the amount of products. E. reaction rates are in balance.
In seed plants,
a. xylem conveys sugar from the production site to the storage site. b. fertilization requires water. c. fertilization produces a zygote within the pollen sac. d. male gametophyte and female gametophyte develop independently. e. microspores enlarge to become megaspores.